<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script>
			// 五个特殊的值: "" 0 undefined NaN
			var age = 20;
			if(age){
				console.log("正常打印内容")
			}
			
			var name = "";
			if(name){
				console.log("我也正常打印内容");
			}
			
		</script>
	</body>
</html>
